A 'Y' harness will distribute the same receiver connection to two different servos. The pulse signal it transfers to the attached servos will be exactly the same. So a 'simple' answer is 'yes'.
This is a simple solution to making two servos work from one channel. You might need a more complicated arrangement. For example, a servo in the right wing might need to operate in the reverse direction as the one in the left wing. The 'Y' harness will not make that happen since both servos attached to the 'Y' harness are handed the same 'pulse' changes. If you have a servo reversing switch on the transmitter and you change that switch then it will reverse BOTH servos which does not solve the problem. The solution here would be to take one of the servos apart and reverse the direction of that servo internally. This is somewhat complicated for most people.
If your system is set up so that you can plug in the 'Y' cable and you can adjust the linkage so that the correct travel will exist for each aileron then you can use the 'Y' cable without any major concerns.
If the cables going to the servos in the wings have a significant distance to travel (if they are LONG cables) then another concern would be that the long cables would pick up stray RF from other sources and cause control problems, generally 'gliching' movement of the servos. The solution for this would be the use some type of 'RF CHOKE' around the wires to attempt to eliminate the RF from traveling on the wires. These are generally found already existing in 'servo extension cables' commercially manufactured. Usually the 'RF CHOKE' looks like a small round ring that is made of special material and there is one on each end of the extension. The ring is called a 'TOROID'. The cables are wrapped around the toroid. These 'CHOKE' off RF frequency signals that may attempt to travel on the wires.